The prior art is replete with a wide variety of methods of treating gas streams, such as natural gas streams, to remove gaseous constituents such as hydrogen sulfide, carbon dioxide and the like.
In these days of scarce energy sources, the value of low pressure natural gas streams has become great enough to make it worthwhile to have low pressure gas gathering systems and to sell the resulting collected gas streams. Particularly, in the early days of the oil field, natural gas was looked on as a dreg and was sold at anywhere from 0.05 to 0.17 dollars per thousand cubic feet (MCF). Nowadays it is possible to collect above $2.00 pr MCF of natural gas. Accordingly, many low pressure streams, some operating even down into vacuum range have been employed as a collection means for collecting the natural gas streams. Vacuum collection, however, is risky in that there is an influx of oxygen containing gas, or air, if there is a leak. Consequently, many sales streams will limit the maximum concentration of oxygen allowed in the sales stream and no good method has been achieved thus far for removing the oxygen which is not necessarily a dissolved oxygen and which is in the presence of a high concentration of other contaminants such as hydrogen sulfide.
Accordingly, it is a desirable feature of this invention to provide a method of achieving a low concentration of oxygen below a predetermined maximum concentration while remaining economically feasible and without providing insurmountable technical problems.
It is also a desirable feature of this invention to provide a method of removing from natural gas stream, containing other contaminants, oxygen without using liquid solution such as a bisulfite solution which are typically used to remove oxygen after it has been dissolved.
These features have not been provided by the prior art.